Yarn feeding apparatus having yarn break protection

ABSTRACT

Yarn feeding apparatus for a knitting machine in which a rotary cap driven by a motor is provided at the top of a storage drum. Optionally, an idle pulley may also be provided adjacent the lower portion of a driving wheel and a mechanism for shifting the driving belt alternately between the driving wheel or idle pulley, so that the driving of the machine is stopped in case of abnormal tension imparted to a feeding yarn. Shifting to either constant feeding or free feeding of yarn is possible to be executed automatically. Automation is possible for work for forming the yarn loop on the storage drum without requiring manual operation one-by-one by an operator. Therefore, it helps avoid poor knitting quality and thus avoids cutting off the yarn. It serves to automate the knitting machine so that constant feeding and free feeding of yarn are simply and conveniently executed.

TECHNICAL FIELD

The present invention relates to a yarn feeding apparatus for a knittingmachine and, more particularly, to a yarn feeding apparatus which, inresponse to abnormal tension on the yarn, allows a yarn loop wound on astorage drum to be unwound, and then halts operation of the machine,whereby the yarn will not break, and thus yarn feeding can be readilyresumed.

BACKGROUND ART

In general, a knitting machine includes a number of yarn feedingapparatuses corresponding to the number of bobbins in order to feed eachyarn as it is unwound from each bobbin to knitting needles within theinterior of the knitting machine. An example of such a yarn feedingapparatus is disclosed in Korean Patent Publication No. 86-1053. Suchapparatus has a storage drum equipped with a driving wheel driven by anendless tape. A number of conical surfaces are provided coaxially witheach other at the upper and lower portions of a holder. Winding andunwinding is simultaneously executed to wind each yarn a predeterminednumber of turns around a storage drum.

In such an apparatus, the yarn arranged on the storage drum smoothlyfeeds yarn to the interior of the knitting machine. However, since anoperator winds the yarn one-by-one on the storage drum to form each yarnloop, not only is the work cumbersome, but it also causes feedingtension differences in each yarn where the number of turns of yarnformed on each storage drum are different from each other.

In presently known and used yarn feeding apparatus, when abnormaltension is imparted to the yarn which is being unwound from the bobbindue to any defect in the bobbin itself, there is no mechanism capable ofabsorbing the increased tension. Therefore, the yarn will often breakeasily.

Further, when it is desired to change over from a positive type feedingto a free feeding to accommodate a switch in textile structure,generally, either a driving belt wound on the driving wheel is manuallyremoved, or a locking device mounted on each driving wheel is handledone-by-one to allow the storage drum to be freely rotated. However,since these changeover processes are cumbersome and difficult toautomate, there has been a problem that productivity is reduced.

SUMMARY OF THE INVENTION

Therefore, the present invention provides a yarn feeding apparatus for aknitting machine in which a rotary cap driven by a motor is provided onan upper part of a storage drum. The structure is such that, when anabnormal tension is imparted to the yarn fed thereto, the yarn loopwound on the storage drum unwinds, and, simultaneously, the driving ofthe machine is stopped, so that the yarn feeding can be executed withoutbreaking or disconnecting the yarn.

The present invention also provides a yarn feeding apparatus for aknitting machine in which an idle pulley is provided adjacent to thebottom of a driving wheel. A shifting mechanism for shifting a drivingbelt to either the driving wheel or the idle pulley is provided at oneside. The shifting mechanism serves to change the yarn feeding conditionbetween positive feeding or free feeding under motor control.

According to one embodiment of the present invention, a hollow shaft isfixed at the central portion of the base of a hollow holder The holderis equipped with a clamper at a side of the holder. A driving wheelequipped integrally with a storage drum above it is rotatably mountedvia a bearing to the hollow shaft. A cylindrical mounting member isattached to the top end of the hollow shaft to support a motor in theinterior of the mounting member, whereby it is located at the inside ofthe storage drum. A hollow threaded tube formed with female threads onthe internal circumferential surface is fixed on the upper surface ofthe motor, and a coupling member having a rectangular section is fixedto the rotary shaft of the motor. A movable threaded tube formed withmale thread on the external circumferential surface thereof and having arectangular groove to be coupled with the coupling member fixed to therotary shaft of the motor is engaged with the hollow threaded tube. Arotary cap having a semispherical surface at an upper end portion isfixed to the top end of the movable threaded tube. A protrusion having ayarn-inducing hole is provided on a side of the semispherical surface ofthe rotary cap, and another yarn-inducing hole is provided at the bottomend portion of the rotary cap directly below the protrusion, whereby itis made such that the yarn to be passed through the first and secondyarn-inducing holes is made to be wound on the storage drum in responseto the rotation of the rotary cap. A push button switch is provided atthe neck portion of the hollow holder. The rotary cap is moved to itsupper position according to the rotation of the motor, the switch buttonis pressed by the protrusion of the rotary cap, and in response thereto,the apparatus stops rotation of the rotary cap and simultaneously causesthe driving wheel and the storage drum to rotate by applying drivingforce to the driving belt and thereby the feeding of yarn is executed.By rotating the cap until it moves from its lower position to the upperposition, the protrusion will press the button portion of the pushbutton switch. The rotary cap has, at this time, wound yarn onto thedrum in an amount determined by the turning number of the rotary capbetween the lower and upper positions. The driving of the knittingmachine is started when the rotary cap is stopped due to the switch.Thereafter, the amount of yarn wound on the storage drum is maintainedas yarn feeding continues as the knitting machine pulls on the yarn.When an abnormal tension is imparted to the yarn being supplied in thisstate, e.g., due to phenomena occurring at the bobbin, the protrusion ofthe rotary cap is released from the push button switch due to thetensional force, and then the storage drum and the rotary cap aresimultaneously rotated, and thereby the yarn loop formed on the storagedrum becomes unwound, whereby the feeding of yarn to the machinecontinues to be executed. Simultaneously with this, since the pressedstate of the button portion of the push button switch becomes released,the operation of the knitting machine is stopped, whereby breaking ofthe yarn can be prevented by stopping the knitting machine before all ofthe yarn wound on the drum is used up.

A preferred embodiment of the present invention as above is for constantfeeding of yarn, but according to another embodiment of the presentinvention, the yarn can be freely fed upon knitting of tissue, such as ajacquard tissue, only by adding simple components. That is, the feedingapparatus is adapted such that the bottom end portion of the hollowshaft is extended, and an idle pulley is provided between the drivingwheel and base portion of the holder. A driving belt shifting pulley tobe shifted by a motor capable of rotating in normal and reversedirections is provided at an appropriate position. For constant feedingof yarn, the driving belt is made to be wound on the driving wheel, andfor free feeding of yarn, the driving belt shifting pulley is made to bedropped down by the rotation of a motor, whereby the driving belt ismade to be wound on the idle pulley, so that the storage drum can befreely rotated according to the pulling force of the knitting machineitself.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a yarn feeding apparatus according to apreferred embodiment of the present invention adapted for use with aknitting machine;

FIG. 2 is a longitudinal cross-sectional view of FIG. 1;

FIG. 3 is a longitudinal cross-sectional view of a yarn feedingapparatus according to a preferred embodiment of the present inventionshowing a state where yarn is being fed during operation of the knittingmachine; and

FIGS. 4 and 5 are schematic explanatory diagrams of a yarn feedingapparatus according to another embodiment of the present invention, inwhich FIG. 4 is a side view showing the apparatus during feeding of theyarn, and FIG. 5 is a side view showing the apparatus during freefeeding of the yarn.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the preferred embodiments of the present invention will bedescribed in detail with reference to the accompanying drawings In thedrawings, i.e., FIGS. 1-3, a yarn feeding apparatus has a clamper 12 forfixing a hollow holder 10 to a supporting ring 11 of a knitting machine.The clamper is provided at a vertical position at one side of the yarnfeeding apparatus. The apparatus also has a hollow shaft 14 which isfixed at its bottom end to a central side of a base 13 by a nut 17acting through washers 15 and 16. A driving wheel 20, having upper andlower flanges 20a and 20b, is rotatably mounted to the hollow shaft 14at the top side of base 13 via a bearing 18. A storage drum 22 hasconical surfaces 22a and 22b and is provided with a number of pins 21("spinning pins") at predetermined intervals on the external surfacethereof to assist in supporting yarn on the drum. The drum 22 is formedintegrally with the driving wheel 20.

A mounting member 19 of cylindrical shape is attached to the top endportion of hollow shaft 14, and a motor 23 is inserted and fixed withinthe interior of the mounting member so as to be located within theinterior of the storage drum 22. A hollow threaded tube 23, having afemale thread portion on its internal circumferential surface, is fixedon the top surface of the motor 23, and a coupling member 25 havingrectangular section is attached to a rotary shaft 23a of the motor. Amovable threaded tube 26, formed with a male thread portion on itsexternal circumferential surface and having a rectangular groove 26b tobe coupled with said coupling member 25 at the internal circumferentialsurface of the tube 26, is coupled at its external surface with thehollow threaded tube 24.

A rotary cap 27, having a semispherical-shaped surface at its top end,is fixed to the top end of the movable threaded tube 26 such that therotary cap 27 almost surrounds the storage drum 22 when the movablethreaded tube 26 is completely threaded onto the hollow tube 24. Aprotective cap 28, having a slightly larger diameter than the hollowthreaded tube 24 and having a length about equal to that of the movablethreaded tube 26, is fixed to the inner side of the rotary cap 27 inorder to prevent any extraneous substances, such as dust, from enteringthe threaded portion of the movable threaded tube 26. Stops 24a and 29aare respectively formed at a top end portion of the hollow threaded tube24 and at a washer 29 fixed to the front end side of the movablethreaded tube 26 in order to limit the lower movement of the cap 27. Aprotrusion 30, having a third yarn-inducing hole 30a, is provided at aside of the semispherical surface of the rotary cap 27, and a fourthyarn-inducing hole 31 is provided at the bottom end of the rotary cap 27substantially vertically below protrusion 30.

A push button switch 33 protrudes inward from a neck portion of hollowholder 10. A knob 32 is also provided at the neck portion of the hollowholder 10 to adjust how much button 33 protrudes. When the button of theswitch 33 is contacted and depressed by the protrusion 30 of the rotarycap 27, rotation of the rotary cap is stopped. Simultaneously, thedriving of the knitting machine is started, and then the driving wheel20 and the storage drum 22 are rotated according to the driving force ofthe driving belt 34, so that the yarn is fed. A yarn stopper 35 isprovided at the front end portion of the hollow holder 10, and first andsecond yarn-inducing holes 36 and 37 located on the rotational center ofthe rotary cap 27 are arranged at upper and lower sides of the yarnstopper 35, and a yarn-running sensor 39 and a yarn-stopping sensor 40are respectively provided at the neck portion and the vertical portionof the hollow holder 10. A fifth yarn-inducing hole 41 receives the endof the yarn which has passed through the first, second, third, andfourth yarn-inducing holes 36, 37, 30a, and 31 and which has been woundon the storage drum 22. This end of the yarn passes through hole 41 tothe interior of the knitting machine.

A signal lamp 42 is provided so that when a yarn becomes disconnected orits feeding stops, the lamp indicates such disconnection or stoppage. Aterminal jack 43 is provided electrically connecting push button switch33, yarn-running sensor 39, yarn-stopping sensor 40, and motor 23 to acentral control unit provided in the main body of the knitting machine.

In the above embodiment, the upper and lower conical surfaces 22a and22b of the storage drum 22 are shown as formed on the storage drumitself, but they also may be formed by bending the upper and lower endportions of the pins 21 so as to have an appropriate slant angle. It isalso possible to eliminate the pins 21 by integrally forming a concaveand convex portion on the surface of the storage drum 22 of the sameshape as the pins 21, respectively.

The motor 23 for rotating cap 27 is a DC motor capable of normal andreverse rotation and preferably is one that can be driven selectively byelectric power of 6V, 9V, 12V, or 24V, according to the kind of yarn tobe fed. The stops 24a and 29a formed on the fixed washer 29 of themovable threaded tube 26 and the top end portion of the hollow threadedtube 24, respectively, are desirable to be formed so that the fourthyarn-inducing hole 31 of the rotary cap 27 is located at a closestposition to the fifth yarn-inducing hole 41 on the holder 10 when therotary cap 27 is located at the lower position, that is, when the stops24a and 29a contact each other.

The operational condition and effect of the yarn feeding apparatusaccording to a preferred embodiment of the present invention having theconstruction as above will be described in detail hereinafter.

When the knitting machine is in a stopped state, the rotary cap 27 islocated at a lower position, as shown in FIGS. 1 and 2. At this time,the yarn from the bobbin is connected to the interior of the knittingmachine through the first and second yarn-inducing holes 36 and 37 ofthe holder 10, the third and fourth yarn-inducing holes 31a and 31provided at the protrusion 30 and the lower peripheral portion of therotary cap 27, and the fifth yarn-inducing hole 41 of the holder 10. Inthis state, when electric power supply is fed from the central controlunit of the knitting machine to the motor 23 to rotate the motor 23, themovable threaded tube 26 and the rotary cap 27 are rotated and moveupward, and thereby wind the yarn onto the storage drum 22, thus formingyarn loops corresponding to the number of turns of the cap 27. The motor23 is stopped at the moment that the rotary cap 27 has executed apredetermined number of rotations, i.e., when the protrusion 30 formedon the semispherical surface contacts the button portion of the pushbutton switch 33 mounted on the neck portion of the holder 10, andthereby the protrusion 30 of the rotary cap 27 presses the push buttonswitch 33. In response, the central control unit of the knitting machinedrives the knitting machine. The driving force of the knitting machineis transmitted to the driving wheel 20 through the driving belt 34,whereby the driving wheel 20 and the storage drum 22 are simultaneouslyrotated. This causes the yarn to be constantly fed into the interior ofthe knitting machine. At this moment, since the driving wheel 20 and thestorage drum 22 are rotated while the rotary cap 27 is stopped, the yarnbeing wound from the storage drum 22 is simultaneously replaced withyarn being wound onto the drum, due to the rotation of the drum.

For the number of turns of such yarn wound on the drum, i.e., the yarnto be wound on the storage drum 22, adjustment is possible according tothe desired requirements. That is, the upper limit of movement of therotary cap 27 can be appropriately selected by adjusting the amount ofprotrusion of the push button switch 33 by using knob 32. Generally,even though the desired total length of the yarn wound around thestorage drum 22 may vary, depending upon the kind or strength of theyarn, it will usually be sufficient if the total length is approximately1.5 m. If the circumference of the storage drum 22 is approximately 15cm, to obtain the 1.5 m of yarn on the drum, the cap must rotate tentimes. Therefore, the button portion of the push button switch 33 andthe protrusion 30 of the cap 27 are made to contact at an upper positioncorresponding to about 10 turns from the lower position of the cap 27.

As described above, as the yarn is being fed to the knitting machine, ifa tension of more than a predetermined amount is imparted to the feedingyarn due to a defect at the bobbin, the protrusion 30 of the rotary cap27 is pulled away from the push button switch 33 by the yarn pullingforce of the knitting machine itself, due to the loss of slack in theyarn from the bobbin. The rotary cap 27 will thus rotate together withthe storage drum 22. In this state, substantially no new yarn will bewound on the storage drum 22, so the amount of yarn wound on the drumwill be reducing as the knitting machine uses it up. As can be seen,even though the yarn feeding to the storage drum 22 has stopped, theyarn feeding to the interior of the knitting machine is not instantlystopped. As noted above, simultaneously with the reduction in yarn onthe drum, the rotary cap 27 rotates in reverse direction (relative tothe above description of initial winding of yarn onto the drum), so thecap 27 moves to the lower position. Accordingly protrusion 30 comes freefrom the push button switch 33. Therefore, the switch 33 returns to theOFF state, whereby the driving of the knitting machine is stopped by thecentral processing unit. The abnormal tension being imparted to thefeeding yarn is usually due to phenomena that cause the yarn wound onthe bobbin to instantaneously stop unwinding. As noted above, if thistension is sufficient, the cap 27 will be pulled and will rotate to movedownward, thus causing the knitting machine to stop. To restart themachine, motor 23 is pulsed toward the upper position. Therefore, anelectric current of 6V, 9V, 12V, or 24V is fed again from 2 to 3 timesfor about 1.5 seconds each time (under the control of the centralcontrol unit). Thus, after 4-5 seconds elapses from stoppage of theknitting machine, i.e., after two to three pulses, if the tensionimparted to the yarn was due to a simple defect of the bobbin, the yarnwill not break and will be quickly loosened by the pulsing, and willre-feed so that cap 27 moves upward again to contact the protrusion 30and switch 33, thereby automatically resuming an operating condition ofthe knitting machine. However, when the abnormal tension persists, evenafter stoppage of the knitting machine, and after the above pulsing, asignal lamp 42 is lit, and at the same time, a signal tone is sounded tothereby prompt an operator to manually check the feeding condition ofthe yarn.

In the above description, the driving voltage fed to the motor 23 isselectively determined, depending upon the kind and strength of theyarn. For a yarn which is weak in strength, such as cotton yarn, a weakvoltage of about 6V is fed. For a yarn which is relatively strong, suchas polyethylene yarn, a strong voltage of about 12V or 24V is used.

According to a preferred embodiment of the present invention as above,automation is possible for the operation of forming the yarn loop on thestorage drum by rotating the rotary cap by utilizing a motor. Therefore,no one-by-one manual operation is required. Further, when an abnormaltension is imparted to a feeding yarn, the rotary cap and the storagedrum are made to be simultaneously rotated, and thereby the yarn woundon the storage drum unwinds to alleviate the tension. If the tensionremains, the knitting machine will automatically be stopped in responseto downward movement of the cap. Thereafter, if there is still abnormaltension, the motor will be pulsed to eliminate it. If the tension stillremains, the feeder indicates this. Therefore, poor knitting isminimized or avoided by minimizing or avoiding breakage of the yarn.

Hereinafter another embodiment of the present invention will bedescribed in detail with reference to FIGS. 4 and 5. In the drawings,for the simplicity of expression, diagrams of such parts having the sameconstruction as in the first embodiment of the present invention areomitted, and components which are the same as in the first embodimentare represented by the same reference numerals.

As shown in FIGS. 4 and 5, an idle pulley 43 is provided via a bearing(not shown) coaxially with the driving wheel 20 at the extended endportion of hollow shaft 14, and a reduction motor 50, capable of normaland reverse rotation and having a screw shaft 51, is mounted at one sidethereof. A U-shaped support frame 52 is coupled to screw shaft 51, and ashifting wheel 54 guided by a guide shaft 53 is mounted to the interiorof a support frame 52. Annular flanges 54a and 54b are providedrespectively to the wheel 54 so that the driving belt 34 will not beremoved therefrom when shifting the driving belt to either the drivingwheel or the idle pulley 43 by the rotation of the reduction motor 50.The driving wheel 20 and the idle pulley 43 are not equipped with anyflanges at their adjacent portions so that the shifting of the drivingbelt 34 is smooth.

This embodiment is applicable when free feeding of the yarn is requiredin order to change the fiber tissue. For example, if a constant feedingof the yarn is required, such as for plain tissue, the driving belt 34is wound on the driving wheel 20, as shown in FIG. 4, and when freefeeding of the yarn is required, such as for jacquard tissue, theshifting wheel 54 is made to drop down by driving the reduction motor50, so that the driving belt 34 is removed from the driving wheel and iswound on the idle pulley 43. Therefore, the storage drum 22 is free,thereby enabling free yarn feeding in response to the pulling force ofthe knitting machine itself.

In this embodiment, not only is the shifting of the constant feeding andfree feeding of the yarn simple and convenient but also it helps furtherautomate the knitting machine.

I claim:
 1. A yarn feeding apparatus for a knitting machine,comprising:a holder having a clamper for fixing to a support ring of theknitting machine and first and second yarn-inducing holes at a front endportion of the holder; a hollow shaft fixed to a base portion of saidholder; a driving wheel rotatably mounted to said hollow shaft anddriven by a driving belt; a storage drum on which pins are arranged atpredetermined intervals on its external circumferential surface andhaving upper and lower conical surfaces, said storage drum being mountedto said driving wheel for rotation therewith; a motor located within theinterior of said storage drum and fixed by a fixing member attached to afront end portion of said hollow shaft, and having a rotary shaftprotruding therefrom; a hollow threaded tube fixed to said motor aroundsaid rotary shaft; a movable threaded tube mounted to the rotary shaftof said motor for rotational movement with the rotary shaft and threadedto said hollow threaded tube; a rotary cap fixed to a front end portionof said movable threaded tube and having a semispherical surface at anupper portion, said rotary cap being movable between lower and upperpositions in response to rotation of said rotary shaft; a protrusionprovided on the semispherical surface of said rotary cap and having athird yarn-inducing hole formed in said protrusion; a push button switchprovided at a neck portion of said holder in a position corresponding toa position of the protrusion at the upper position of said rotary cap; afourth yarn-inducing hole arranged at a bottom side portion of saidprotrusion; and a fifth yarn inducing hole arranged at a verticalportion of the holder, wherein upper and lower conical surfaces of saidstorage drum are formed by bending upper and lower end portions of thepins.
 2. The yarn feeding apparatus according to claim 1, wherein saiddriving wheel and storage drum are integrally formed by the pins.
 3. Theyarn feeding apparatus according to claim 1, wherein first and secondmechanical stops are formed on a front end portion of said hollowthreaded tube and on a bottom surface to a washer for fixing said rotarycap, respectively, for contacting each other when said rotary cap is inthe lower position, and wherein when said rotary cap is in the lowerposition, said fourth yarn-inducing hole and said fifth yarn-inducinghole are located in positions closest to each other, relative to whensaid rotary cap is in positions other than said lower position.
 4. Theyarn feeding apparatus according to claim 1, wherein a protection caphaving a length almost the same as said movable threaded tube and adiameter slightly larger than a diameter of said hollow helical tube isattached to the bottom surface of said rotary cap.
 5. The yarn feedingapparatus for a knitting machine, comprising:a storage drum for havingyarn from a bobbin wound thereon and for supplying the yarn woundthereon to the knitting machine; means for rotatably mounting thestorage drum to the support, and means for rotating the storage drum; amotor supported in the storage drum; a rotary cap; means for connectingthe rotary cap to the motor for rotating the rotary cap in response toenergizing of the motor to move the rotary cap away from the storagedrum in response to rotation of the rotary cap in one direction andtoward the storage drum in response to rotation of the rotary cap in theother direction; a switch mounted on the support actuable for turningoff the motor and turning on the knitting machine, wherein the rotarycap has a contact for contacting the switch to actuate the switch; meansattached to the support for guiding yarn from the bobbin; means attachedto the rotary cap for further guiding yarn after the yarn passes fromthe yarn guiding means, and for winding the yarn onto the storage drumin response to rotation of the rotary cap; and means attached to thesupport for still further guiding yarn from the storage drum to theknitting machine, wherein movement of the rotary cap away from thestorage drum is adapted to wind the yarn onto the storage drum until thecontact contacts the switch, thereby turning off the motor and turningon the knitting machine.
 6. The yarn feeding apparatus of claim 5,wherein the means for connecting the rotary cap includes a movablethreaded tube for enabling rotation of the rotary cap in the otherdirection in response to the yarn on the storage drum being unwound bythe knitting machine faster than yarn is being wound onto the storagedrum.
 7. The yarn feeding apparatus of claim 6, wherein the switchincludes means for de-actuation in response to movement of the rotarycap toward the storage drum and, in response thereto, the knittingmachine is de-activated, wherein the motor is responsive to de-actuationof the switch, and wherein the motor is initially pulsed on and off inresponse to de-actuation of the switch, then maintained on until thecontact contacts the switch, and further comprising means for providingan indication in response to failure of the contact to contact theswitch within a predetermined time.
 8. A yarn feeding apparatus for aknitting machine, comprising:a holder having a clamper for fixing to asupport ring of the knitting machine and first and second yarn-inducingholes at a front end portion of the holder; a hollow shaft fixed to abase portion of said holder; a driving wheel rotatably mounted to saidhollow shaft and driven by a driving belt; a storage drum on which pinsare arranged at predetermined intervals on its external circumferentialsurface and having upper and lower conical surfaces, said storage drumbeing mounted to said driving wheel for rotation therewith; a motorlocated within the interior of said storage drum and fixed by a fixingmember attached to a front end portion of said hollow shaft, and havinga rotary shaft protruding therefrom; a hollow threaded tube fixed tosaid motor around said rotary shaft; a movable threaded tube mounted tothe rotary shaft of said motor for rotational movement with the rotaryshaft and threaded to said hollow threaded tube; a rotary cap fixed to afront end portion of said movable threaded tube and having asemispherical surface at an upper portion, said rotary cap being movablebetween lower and upper positions in response to rotation of said rotaryshaft; a protrusion provided on the semispherical surface of said rotarycap and having a third yarn-inducing hole formed in said protrusion; apush button switch provided at a neck portion of said holder in aposition corresponding to a position of the protrusion at the upperposition of said rotary cap; a fourth yarn-inducing hole arranged at abottom side portion of said protrusion; and a fifth yarn inducing holearranged at a vertical portion of the holder, wherein said first andsecond yarn-inducing holes are located on a rotational central axis ofsaid rotary cap.
 9. A yarn feeding apparatus for a knitting machine,comprising:a holder having a clamper for fixing to a support ring of theknitting machine and first and second yarn-inducing holes at a front endportion of the holder; a hollow shaft fixed to a base portion of saidholder; a driving wheel rotatably mounted to said hollow shaft anddriven by a driving belt; a storage drum on which pins are arranged atpredetermined intervals on its external circumferential surface andhaving upper and lower conical surfaces, said storage drum being mountedto said driving wheel for rotation therewith; a motor located within theinterior of said storage drum and fixed by a fixing member attached to afront end portion of said hollow shaft, and having a rotary shaftprotruding therefrom; a hollow threaded tube fixed to said motor aroundsaid rotary shaft; a movable threaded tube mounted to the rotary shaftof said motor for rotational movement with the rotary shaft and threadedto said hollow threaded tube; a rotary cap fixed to a front end portionof said movable threaded tube and having a semispherical surface at anupper portion, said rotary cap being movable between lower and upperpositions in response to rotation of said rotary shaft; a protrusionprovided on the semispherical surface of said rotary cap and having athird yarn-inducing hole formed in said protrusion; a push button switchprovided at a neck portion of said holder in a position corresponding toa position of the protrusion at the upper position of said rotary cap; afourth yarn-inducing hole arranged at a bottom side portion of saidprotrusion; and a fifth yarn inducing hole arranged at a verticalportion of the holder, wherein said motor is selectively driven by DC6V, 9V, 12V, or 24V and capable of rotating in normal and reversedirections.
 10. A yarn feeding apparatus for a knitting machine,comprising:a holder having a clamper for fixing to a support ring of theknitting machine and first and second yarn-inducing holes at a front endportion of the holder; a hollow shaft fixed to a base portion of saidholder; a driving wheel rotatably mounted to said hollow shaft anddriven by a driving belt; a storage drum on which pins are arranged atpredetermined intervals on its external circumferential surface andhaving upper and lower conical surfaces, said storage drum being mountedto said driving wheel for rotation therewith; a motor located within theinterior of said storage drum and fixed by a fixing member attached to afront end portion of said hollow shaft, and having a rotary shaftprotruding therefrom; a hollow threaded tube fixed to said motor aroundsaid rotary shaft; a movable threaded tube mounted to the rotary shaftof said motor for rotational movement with the rotary shaft and threadedto said hollow threaded tube; a rotary cap fixed to a front end portionof said movable threaded tube and having a semispherical surface at anupper portion, said rotary cap being movable between lower and upperpositions in response to rotation of said rotary shaft; a protrusionprovided on the semispherical surface of said rotary cap and having athird yarn-inducing hole formed in said protrusion; a push button switchprovided at a neck portion of said holder in a position corresponding toa position of the protrusion at the upper position of said rotary cap; afourth yarn-inducing hole arranged at a bottom side portion of saidprotrusion; and a fifth yarn inducing hole arranged at a verticalportion of the holder, wherein said push button switch extends from saidneck portion a predetermined amount, said predetermined amount isadjustable by means of an adjusting knob.
 11. The yarn feeding apparatusaccording to claim 10, wherein the predetermined amount defines theupper position of said rotary cap, and thereby limits a number ofrotations of said rotary cap from the lower position to the upperposition.
 12. A yarn feeding apparatus for a knitting machine,comprising:a holder having a clamper for fixing to a support ring of theknitting machine and first and second yarn-inducing holes at a front endportion of the holder; a hollow shaft fixed to a base portion of saidholder; a driving wheel rotatably mounted to said hollow shaft anddriven by a driving belt; a storage drum on which pins are arranged atpredetermined intervals on its external circumferential surface andhaving upper and lower conical surfaces, said storage drum being mountedto said driving wheel for rotation therewith; a motor located within theinterior of said storage drum and fixed by a fixing member attached to afront end portion of said hollow shaft, and having a rotary shaftprotruding therefrom; a hollow threaded tube fixed to said motor aroundsaid rotary shaft; a movable threaded tube mounted to the rotary shaftof said motor for rotational movement with the rotary shaft and threadedto said hollow threaded tube; a rotary cap fixed to a front end portionof said movable threaded tube and having a semispherical surface at anupper portion, said rotary cap being movable between lower and upperpositions in response to rotation of said rotary shaft; a protrusionprovided on the semispherical surface of said rotary cap and having athird yarn-inducing hole formed in said protrusion; a push button switchprovided at a neck portion of said holder in a position corresponding toa position of the protrusion at the upper position of said rotary cap; afourth yarn-inducing hole arranged at a bottom side portion of saidprotrusion; and a fifth yarn inducing hole arranged at a verticalportion of the holder, wherein an idle pulley is mounted coaxially at alower portion of said driving wheel, and said apparatus furthercomprises means for selectively shifting the driving belt to one of saiddriving wheel and said idle pulley.
 13. The yarn feeding apparatusaccording to claim 12, wherein said shifting means includes a reductionmotor having a screw shaft and capable of rotating in normal and reversedirections, a support frame shifted by the rotation of said screw shaft,a guide rod for guiding said support frame, and a shifting wheel movablymounted along the guide rod at an interior of said support frame.